velocity sensitivity - how does it work?
velocity sensitivity - how does it work? Posted on: 01.03.2010 by Rebbecca Fennell How does it work? Is there a way to implement it into an arcade mod?If the microcontroller is able to recognize, recieve, and transmit this info - there's got to be a way to implement it in an arcade button | |
| Patsy Klapman 12.02.2014 |
Originally Posted by mastercon12
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| Rebbecca Fennell 12.03.2010 |
Originally Posted by CerebralExcretion
I'm believeing if I keep the rubber contacts I could make a new key bed with shorter keys and a round raised arcade button like surface. Just have that part coming out from under the new faceplate of the casing. Your idea sounds intriguing tho, would that work with a mod or is that only if you make your own controller? Keep us posted |
| Gianna Renfer 12.03.2010 |
Originally Posted by CerebralExcretion
I'd love to see your results, video your experiment?? I put a piezo in a neoprene drum practice pad and hooked it up to an drum sound module and it worked fine, i didn't have to hit very hard to get a 127 velocity reading out of it though and it would give reading if i tapped the desk it was sitting on.... i also did not have to mod the module. how would the piezo signal be transmitted? along the same signal cable as +/- as the button?? |
| Rebbecca Fennell 01.03.2010 | How does it work? Is there a way to implement it into an arcade mod? If the microcontroller is able to recognize, recieve, and transmit this info - there's got to be a way to implement it in an arcade button |
| Rebbecca Fennell 12.03.2010 |
Originally Posted by CerebralExcretion
I'm believeing if I keep the rubber contacts I could make a new key bed with shorter keys and a round raised arcade button like surface. Just have that part coming out from under the new faceplate of the casing. Your idea sounds intriguing tho, would that work with a mod or is that only if you make your own controller? Keep us posted |
| Gianna Renfer 12.03.2010 |
Originally Posted by CerebralExcretion
I'd love to see your results, video your experiment?? I put a piezo in a neoprene drum practice pad and hooked it up to an drum sound module and it worked fine, i didn't have to hit very hard to get a 127 velocity reading out of it though and it would give reading if i tapped the desk it was sitting on.... i also did not have to mod the module. how would the piezo signal be transmitted? along the same signal cable as +/- as the button?? |
| Adolf Hit 11.03.2010 | You could get basic velocity info from timing the bounce of the contacts of the arcade buttons, but you would have to scan very fast to get reliable results, and it would still be pretty crap. You either need to use Piezo, or rubberised contact style buttons |
| Iola Obradovich 11.03.2010 | Are you trying to modify an existing controller or is this a new DIY project? piezo buzzers are cheap, make very good velocity sensitive switches and their allot easyer to impliment than two switches along with a complex algorithem on a PIC. Thinking about it i bet you could mount a small piezo in the underside of an archade button then you would have the appearance and playability of an arcade button with the velocity of a drum pad. Hmm i like the idea of that ill order some parts and have a play. |
| Rebbecca Fennell 05.03.2010 | Sweet, thanks limey. So that's why the contact on a 49 key keyboard has 2 contacts for the switch. Time to see how well those keys take to a dremel drill... |
| robert chanda 03.03.2010 | There are four parameters of a full MIDI key event - channel, pitch, velocity and aftertouch. Velocity is a measure of how fast a switch was pressed, so it requires an element of timing. One way is to have two switches set apart with a standard short "travel" distance. As soon as the first switch is activated start a timer that stops when the second switch is hit and that time is proportional to the velocity. Aftertouch measures how "hard" a button is pressed once it has been activated and is a measure of pressure. These can be done using rubberised resistors that reduce resistance the more they are pressed (e.g. conductive foam being compressed and making a series of shorts through it's volume). There is a third way and that's the rubberised contact. You can see these on the bottom of Monome -style rubber keys. As these rings press on the PCB contacts, they conduct more the harder they are pressed. If you sample the voltage across the switch fast enough and graph this over time you get a nice curve. From this curve you can deduce velocity by measuring how much time it took for the voltage to go from zero to a certain threshold value as speed of a hit is often proportional to how hard it was hit (not always so this is really an approximation...) and the aftertouch is just the value of the curve after the threshold has been passed. That's how the MPD pads work. |
| Rebbecca Fennell 01.03.2010 | Ah thank you mastercon, that was going to be an idea thrown out there - does it work like a lightdimmer where all the dimmer does is inhibit the amount of voltage coming thru. The amount that comes thru is the basis of the value like a potentiometer. |
| Hanna Zitzmann 01.03.2010 | the mpd 16 doesnt have basic contact switches. All the arcade button is doing is completing a circuit. The mpd pads are detecting velocity and sending out different midi data depending on how hard you hit the pads. If I remember correctly, they act similarly to a potentiometer. |
| Rebbecca Fennell 01.03.2010 | I understand you can't turn the light switch into a dimmer switch but obviously there are dimmer switchs that LOOK like regular switchs. And considering all an arcade button is is a springloaded piece of plastic over a switch, I do not believe its impossible with extra stuff to make the necessary changes. Velocity sensitive game pads clearly exist, and if a company can make it so can I or anyone else in theory. Its not magic. Now does anyone have any actual insight into HOW velocity sensitivity works? is it 2 parallel circuits that can measure the time elapsed between the first circuit and the second circuit closing? That would be my first guess. Considering how cheap you can get a controller with velocity sensitivity it must not be that complex if you know the basic mechanism behind it. So does anyone have any real information on the matter? In fact just forget I said the words "arcade button", I just want someone to explain what part of the key circuit takes that information and how is that information generated? |
| juan garcia 01.03.2010 | its kind of like asking if you can turn a lightswitch into dimmer switch you mentioned you see the arcade buttons are momentary on/offs, they are either on or off, and there is no more distinction being made. pad controllers like the mpd don't use the same simple momentary components. |
| Rebbecca Fennell 01.03.2010 | Uh huh well as insightful as that was, no offense, I don't believe you. they're just momentary switchs and when I look at, for an example, the pcb under the keys of a emu xboard 49 its clearly just a basic contact switch. The same is true with an akai mpd16. Both are just basic contact switchs. So unless you are able to define what facet of the switch makes velocity information possible I would prefer not to hear your kurt uninformative answers |
| Hanna Zitzmann 01.03.2010 | there is absolutely no way to add velocity sensitivity to an arcade mod. They are just buttons. |
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